This invention relates to silicon precursor compositions for forming silicon-containing films by low temperature (e.g., <550.degree. C.) chemical vapor deposition processes for fabrication of ULSI devices and device structures. Such silicon precursor compositions comprise at least a silane or disilane derivative that is substituted with at least one alkylhydrazine functional groups and is free of halogen substitutes.

Claim:

What is claimed is:

1. A method of forming a silicon-containing film on a substrate, comprising contacting a substrate under vapor deposition conditions comprising a temperature below450.degree. C. with a vapor of a disilane compound of the formula: ##STR00009## to form said silicon-containing film on the substrate.

2. The method of claim 1, wherein said film comprises silicon dioxide.

3. The method of claim 1, wherein said film comprises silicon nitride.

4. The method of claim 1, wherein said film comprises siliconoxynitride.

5. The method of claim 1, wherein said film comprises a low dielectric constant silicon-containing film.

6. The method of claim 1, wherein said film comprises a gate silicate film.

7. The method of claim 1, wherein said film comprises an epitaxial silicon-containing film.

10. The method of claim 1, conducted in an ULSI device fabrication process.

11. The method of claim 1, wherein said vapor is transported to said contacting at temperature below 300.degree. C.

12. The method of claim 11, wherein said vapor is transported at atmospheric pressure.

13. A method of manufacturing a semiconductor device, comprising using a silicon precursor of the formula: ##STR00010## to deposit at temperature below 450.degree. C. a silicon-containing film on a substrate for said semiconductor device.

14. The method of claim 13, wherein the silicon precursor is used to form a silicon nitride material in said semiconductor device.

15. The method of claim 14, wherein said silicon precursor is used to form a semiconductor device diffusion barrier layer.

16. The method of claim 14, wherein said silicon precursor is used to form a semiconductor device etch-stop layer.

Deposition of silicon nitride films by chemical vapor deposition (CVD) techniques is a highly attractive methodology for forming such films. CVD precursors currently used include bis(tert-butylamino)silane (BTBAS) or silane/ammonia, but suchprecursors usually require deposition temperature higher than 600.degree. C. for forming high quality Si.sub.3N.sub.4 films, which is incompatible with the next generation IC device manufacturing, where deposition temperature of below 500.degree. C.,and preferably about 450.degree. C., is desired. Therefore, development of low-temperature silicon-containing CVD precursors is particularly desired.

Presently, hexachlorodisilane, Cl.sub.3Si--SiCl.sub.3, is being studied as a candidate precursor for low-temperature CVD formation of silicon nitride thin films upon reaction with ammonia gas. The drawbacks of using hexachlorodisilane in CVDprocesses include: (i) formation of large amount of NH.sub.4Cl during the process, which leads to the particle contamination and solid build-up in vacuum system and exhaust lines; (ii) possible chlorine incorporation in the chips, which couldsignificantly reduce their life time and long-term performance; and (iii) the reaction by-products are known to be explosive. It is therefore desirable to develop new chlorine-free precursors that can be used for low-temperature CVD formation of siliconnitride thin films.

SUMMARY OF THE INVENTION

The present invention relates generally to the formation of silicon-containing films, such as films comprising silicon, silicon nitride (Si.sub.3N.sub.4), siliconoxynitride (SiO.sub.xN.sub.y), silicon dioxide (SiO.sub.2), etc., silicon-containinglow k films, high k gate silicates, and silicon epitaxial films, among which silicon nitride thin films are preferred, in the manufacture of semiconductor devices, and more specifically to compositions and methods for forming such silicon-containingfilms.

The present invention in one aspect relates to a group of halogen-free silane or disilane derivatives that are substituted with at least one alkylhydrazine functional groups and can be used as CVD precursors for deposition of silicon-containingthin films.

The silane derivatives of the present invention can be represented by the general formula of:

##STR00001## wherein R.sub.1 and R.sub.2 may be the same as or different from each another and are independently selected from the group consisting of H, C.sub.1-C.sub.7 alkyl, aryl, and C.sub.3-C.sub.6 cycloalkyl, or R.sub.1 and R.sub.2together may form C.sub.3-C.sub.6 heterocyclic functional group with N, and wherein X, Y, and Z may be the same as or different from one another and are independently selected from the group consisting of H, C.sub.1-C.sub.7 alkyl, alkylamino,dialkylamino, and alkylhydrazido (e.g., R.sub.1R.sub.2NNH--, wherein R.sub.1 and R.sub.2 are same as described hereinabove).

Preferably, X, Y, and Z are all identical functional groups. More preferably, X, Y, and Z are all C.sub.1-C.sub.7 alkyl, such as methyl or ethyl. Alternatively but also preferably, X, Y, and Z are all alkylhydrazido (e.g., R.sub.1R.sub.2NNH--,wherein R.sub.1 and R.sub.2 are same as described hereinabove), such as N,N'-dimethylhydrazido or N,N'-diethylhydrazido.

The disilane derivatives of the present invention can be represented by the general formula of:

##STR00002## wherein R.sub.1, R.sub.2, R.sub.3, and R.sub.4 may be the same as or different from each another and are independently selected from the group consisting of H, C.sub.1-C.sub.7 alkyl, aryl, and C.sub.3-C.sub.6 cycloalkyl, or R.sub.1and R.sub.2 together may form C.sub.3-C.sub.6 heterocyclic functional group with N, or R.sub.3 and R.sub.4 together may form C.sub.3-C.sub.6 heterocyclic functional group with N, and wherein X.sub.1, X.sub.2, Y.sub.1, and Y.sub.2 may be the same as ordifferent from one another and are independently selected from the group consisting of H, C.sub.1-C.sub.7 alkyl, alkylamino, dialkylamino, and alkylhydrazido (e.g., R.sub.1R.sub.2NNH--, wherein R.sub.1 and R.sub.2 are same as described hereinabove).

Preferably, the disilane derivative compound of the present invention is characterized by functional groups that are symmetrically distributed in relation to the Si--Si bond.

Preferred silane or disilane derivative compounds of the present invention include, but are not limited to, Me.sub.3Si(HNNMe.sub.2), Si(HNNMe).sub.4, Me.sub.2(HNNMe.sub.2)Si--Si(HNNMe.sub.2)Me.sub.2, and(HNBu.sup.t).sub.2(HNNMe.sub.2)Si--Si(HNNMe.sub.2)(HNBu.sup.t).sub.2, wherein Bu and Me are consistently used as the respective abbreviations of butyl and methyl throughout the text hereinafter.

Another aspect of the present invention relates to a method for forming a silicon-containing film on a substrate, comprising contacting a substrate under chemical vapor deposition conditions including a deposition temperature of below 550.degree. C., preferably below 500.degree. C., and more preferable below 450.degree. C., with a vapor of a silane or disilane derivative compound that is substituted with at least one alkylhydrazine functional group.

Still another aspect of the present invention relates to a method of making such silane or disilane derivative compounds, by reacting silane or disilane compounds comprising one or more halogen groups (i.e., halosilane or halodisilane) withalkylhydrazine in the presence of NEt.sub.3, to substitute the one or more halogen groups of such silane or disilane compounds with alkylhydrazine functional groups.

A still further aspect of the present invention relates to a method of making Me.sub.3Si(HNNMe.sub.2), by reacting Me.sub.3SiCl with approximately one molar ratio of H.sub.2NNMe.sub.2 in the presence of NEt.sub.3, according to the followingreaction:

##STR00003##

A still further aspect of the present invention relates to a method of making Si(HNNMe.sub.2).sub.4, by reacting SiCl.sub.4 with approximately four molar ratio of H.sub.2NNMe.sub.2 in the presence of NEt.sub.3, according to the followingreaction:

##STR00004##

A still further aspect of the present invention relates to a method of making Me.sub.2(HNNMe.sub.2)Si--Si(HNNMe.sub.2)Me.sub.2, by reacting Me.sub.2(Cl)Si--Si(Cl)Me.sub.2 with approximately two molar ratio of H.sub.2NNMe.sub.2 in the presence ofNEt.sub.3, according to the following reaction:

##STR00005##

A still further aspect of the present invention relates to a method of making, by reacting (HNBu.sup.t).sub.2(HNNMe.sub.2)Si--Si(HNNMe.sub.2)(HNBu.sup.t).sub.2, by reacting (HNBu.sup.t).sub.2(Cl)Si--Si(Cl)(HNBu.sup.t).sub.2 with approximately twomolar ratio of LiHNNMe.sub.2, according to the following reaction:

##STR00006##

Other aspects, features and embodiments of the invention will be more fully apparent from the ensuing disclosure and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a STA plot for Si(HNNMe.sub.2).sub.4.

FIG. 2 is an X-ray crystal structure of the compound Si(HNNMe.sub.2).sub.4.

FIG. 3 is a STA plot for Me.sub.2(HNNMe.sub.2)Si--Si(HNNMe.sub.2)Me.sub.2.

FIG. 4 is a STA plot for (HNBu.sup.t).sub.2(HNNMe.sub.2)Si--Si(HNNMe.sub.2)(HNBu.sup.t).sub.2.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS THEREOF

The present invention relates to silicon precursors for CVD formation of films on substrates, such as silicon precursors for forming low k dielectric films, high k gate silicates, low temperature silicon epitaxial films, and films comprisingsilicon, silicon oxide, silicon oxynitride, silicon nitride, etc., as well as to corresponding processes for forming such films with such precursors.

Silane or disilane derivatives that contain one or more alkylhydrazine functional groups, free of any halogen substitutes, are found particularly suitable for low-temperature deposition of silicon nitride thin films, since the bond-strength ofthe nitrogen-nitrogen single bond in the hydrazine functional group relatively weak. Moreover, use of such halogen-free silicon precursors avoids the various problems involved in previous CVD processes using hexachlorodisilane.

Preferred silane derivatives of the present invention can be represented by the general formula of:

##STR00007## wherein R.sub.1 and R.sub.2 may be the same as or different from each another and are independently selected from the group consisting of H, C.sub.1-C.sub.7 alkyl, aryl, and C.sub.3-C.sub.6 cycloalkyl, or R.sub.1 and R.sub.2together may form C.sub.3-C.sub.6 heterocyclic functional group with N, and wherein X, Y, and Z may be the same as or different from one another and are independently selected from the group consisting of H, C.sub.1-C.sub.7 alkyl, alkylamino,dialkylamino, and alkylhydrazido (e.g., R.sub.1R.sub.2NNH--, wherein R.sub.1 and R.sub.2 are same as described hereinabove).

Preferred disilane derivatives of the present invention can be represented by the general formula of:

##STR00008## wherein R.sub.1, R.sub.2, R.sub.3, and R.sub.4 may be the same as or different from each another and are independently selected from the group consisting of H, C.sub.1-C.sub.7 alkyl, aryl, and C.sub.3-C.sub.6 cycloalkyl, or R.sub.1and R.sub.2 together may form C.sub.3-C.sub.6 heterocyclic functional group with N.sub.1 or R.sub.3 and R.sub.4 together may form C.sub.3-C.sub.6 heterocyclic functional group with N, and wherein X.sub.1, X.sub.2, Y.sub.1, and Y.sub.2 may be the same asor different from one another and are independently selected from the group consisting of H, C.sub.1-C.sub.7 alkyl, alkylamino, dialkylamino, and alkylhydrazido (e.g., R.sub.1R.sub.2NNH--, wherein R.sub.1 and R.sub.2 are same as described hereinabove).

Disilane derivative compounds that are substantially symmetrical in structure in relation to the Si--Si bond, i.e., all functional groups of such compounds being symmetrically distributed in relation to the Si--Si bond, are particularly preferredfor practicing of the present invention. For example, such disilane derivative compounds may contain two identical alkylhydrazine functional groups and four identical C.sub.1-C.sub.5 alkyl functional groups that are symmetrically distributed in relationto the Si--Si bond, such as Me.sub.2(HNNMe)Si--Si(HNNMe)Me.sub.2.

The silane or disilane derivative compounds as described hereinabove are advantageously characterized by a vaporization temperature of less than 300.degree. C. Moreover, such compounds can be transported in vapor form at less than 300.degree. C. and under atmospheric pressure, with no or little (<2%) residual material. The silicon-containing films that can be formed using such disilane precursor compounds include Si.sub.3N.sub.4 thin films, high k gate silicates and silicon epitaxialfilms. In a particularly preferred embodiment of the invention, the films formed using such silane or disilane precursors comprise silicon nitride.

Preferred silane or disilane compounds of the above-described formulas include, but are not limited to, Me.sub.3Si(HNNMe.sub.2), Si(HNNMe.sub.2).sub.4, Me.sub.2(HNNMe.sub.2)Si--Si(HNNMe.sub.2)Me.sub.2, and(HNBu.sup.t).sub.2(HNNMe.sub.2)Si--Si(HNNMe.sub.2)(HNBu.sup.t).sub.2.

Synthesis and characterization of the above-listed preferred compounds is described in the following examples:

Example 1

Synthesis and Characterization of Me.sub.3Si(HNNMe.sub.2)

A 3 L flask was filled with a solution comprising 2.5 L hexanes, 54.0 grams (0.53 mol) NEt.sub.3, and 30 grams (0.50 mol) of H.sub.2NNMe.sub.2. 58 grams (0.53 mol) Me.sub.3SiCl, as dissolved in 500 mL of hexanes, was slowly added into the 3 Lflask at 0.degree. C. White precipitate was observed during the addition of Me.sub.3SiCl. After the completion of the reaction, the mixture was warmed to room temperature, stirred overnight, and then filtered. The crude yield was in 80%. Regulardistillation procedure was used to purify the end product, which has a boiling point of approximately 100.degree. C. .sup.1H NMR(C.sub.6D.sub.6): .delta. 0.15 (s, 9H, --SiCH.sub.3), 1.73 (br, 1H, --NH), 2.22 (s, 6H, --NCH.sub.3). .sup.13C{.sup.1H}NMR(C.sub.6D.sub.6): .delta. -0.54 (--SiCH.sub.3), 52.4 (--NCH.sub.3). Mass spectrum: m/z 132 [M.sup.+], 117 [M.sup.+-Me)], 102 [M.sup.+-2Me)], 88 [M.sup.+-3Me)], 73 [M.sup.+-(--HNNMe.sub.2)].

Si(HNNMe.sub.2).sub.4 is a solid material having a melting temperature of approximately 73.degree. C. The thermal stability of Si(HNNMe.sub.2).sub.4 in solution at 100.degree. C. was monitored by proton NMR study for 7 days, and no significantdecomposition was detected.

FIG. 1 is a STA plot for Si(HNNMe.sub.2).sub.4, indicating that Si(HNNMe.sub.2).sub.4 can be transported completely with very little (<2%) residual material at 500.degree. C.

FIG. 2 shows the X-ray crystal structure of Si(HNNMe.sub.2).sub.4.

Example 3

Synthesis and Characterization of Me.sub.2(HNNMe.sub.2)Si--Si(HNNMe.sub.2)M.sub.2

FIG. 3 shows the STA plot for Me.sub.4Si.sub.2(HNNMe.sub.2).sub.2, which is a liquid at room temperature and can be transported in its vapor form completely with very little (<1%) residual material at about 350.degree. C. The thermalstability of Me.sub.4Si.sub.2(HNNMe.sub.2).sub.2 in solution at 100.degree. C. was monitored by proton NMR study for 7 days, and no significant decomposition was detected.

Example 4

Synthesis and Characterization of (HNBu.sup.t).sub.2(HNNMe.sub.2)Si--Si(HNNMe.sub.2)(HNBu.sup.t).sub.2

FIG. 4 shows the STA plot for (HNBu.sup.t).sub.2(HNNMe.sub.2)Si--Si(HNNMe.sub.2)(HNBu.sup.t).sub.2, which is a solid at room temperature and can be transported completely with very little (.about.0.03%) residual material at about 500.degree. C.

Such silane or disilane derivative compounds as described hereinabove can be used for low-pressure CVD deposition of various silicon-containing films, including silicon nitride thin films, consistent with the disclosure in U.S. patentapplication Ser. No. 10/294,431 for "Composition and Method for Low Temperature Deposition of Silicon-Containing Films Including Silicon Nitride, Silicon Dioxide and/or Silicon-Oxynitride" filed on Nov. 14, 2002, now U.S. Pat. No. 7,531,679 issuedMay 12, 2009, the content of which is incorporated by reference in its entirety for all purposes.

While the invention has been described herein with reference to various specific embodiments, it will be appreciated that the invention is not thus limited, and extends to and encompasses various other modifications and embodiments, as will beappreciated by those ordinarily skilled in the art. Accordingly, the invention is intended to be broadly construed and interpreted, in accordance with the ensuing claims.